A conventional pipe cutter generally includes a body made of cast iron, two fixed two  rollers arranged to an inner side of the body and a movable blade disk movably connected to a threaded rod which can be moved by rotating a knob connected to a distal end of the threaded rod. A pipe to be cut can be clamped by the two fixed rollers and the disk blade which is moved twoard the two fixed rollers. By rotating the threaded rod, the disk blade cuts the pipe. However, the speed to move the disk blade is so slow so  that it takes a lot of time to cut the pipe. In addition, the conventional pipe cutter can be only used to cut the  pipe having the  a smaller diameter, because the distance between the two rollers is not adjustable so that a pipe having a large diameter will not be well clamped between the two rollers and the disk blade. Furthermore, the threaded rod can only be moved in a fixed direction and this limits the positions where the rollers are located. All of the three  prior pipe cutters are made in a form of a one-piece article which is made of cast iron which is heavy so that the users cannot use them conveniently. The cost for manufacturing the  conventional pipe cutters is high and therefore reduces the commercial benefit.
The present invention intends to provide an improved pipe cutter wherein one of the two rollers is fixed and the other is movable, the disk blade is movable and pivotally connected to the movable roller by two links so that the two rollers and the blade disk clamp the pipe to be cut evenly on the outside of the pipe, and the pipe cutter of the present invention may clamp pipes with different diameters.